• The Korean Journal of Pharmacology
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• v.18 no.2
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• pp.1-14
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• 1982

The effects of xanthine-xanthine oxidase reaction on brain microsomal $Na^+-K^+-ATPase$ activity were studied to see possible involvement of oxygen free radicals in pathologic change occurring in ischemic state of CNS accompanied by cerebral vascular occlusion or impact injury. When microsomal fraction was incubated with xanthine ana xanthine oxidase, $Na^+-K^+-ATPase$ activity of the fraction was markedly inactivated (80% inactivation) whereas btssl $Mg^{++}-ATPase$ was much less sensitive (less than 10% inactivation) compared to that of $Na^+-K^+-ATPase$. The inactivation was observed only in the presence of both xanthine and xanthine oxidase, not either of them alone, and the extent of inactivation was dependent on the concentration of xanthine. In an attempt to determine which of the oxygen species was responsible for the inactivation, the ability of various scavengers to overcome the inactivation was tested. Superoxide dismutase, catalase and 1,4-diazabicyclo(2,2,2)octane were shown to reverse the inactivation of the ATPase in dose-dependent manner. In contrast, mannitol as well as other $OH{\cdot}$quenchers were ineffective in limiting oxygen radical-induced inactivation. Thus $O_{\bar{2}}{\cdot},\;H_2O_2$ and $^1O_2$ were implicated to be mediators involved in the inactivation. Since oxygen radicals are suspected as being a cause of the peroxidative damaging process in train ischemia, the ATPase inactivation by oxygen radicals may be a possible contributing factor which gives rise to functional derangement of nerve cells observed in the pathologic process.

• The Korean Journal of Physiology
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• v.29 no.1
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• pp.69-80
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• 1995

Renal proximal tubular hypertrophy and hyperfunction are known to be early manifestations of experimental and human diabetes. As the hypertrophy and hyperfunction have been suggested to be central components in the progression to renal failure, an understanding of their underlying causes is potentially important for the development of therapy. A primary rabbit kidney proximal tubule cell culture system was utilized to evaluate the possibility that the renal proximal tubular hypertrophy and hyperfunction observed in vivo in diabetes mellitus, can be attributed to effects of elevated glucose levels on membrane transport systems. Primary cultures of rabbit proximal tubules, which achieved confluence at 10 days, exhibited brush-border characteristics typical of proximal tubular cells. Northern analysis indicated $2.2{\sim}2.3$ and 2.0 kb Na/glucose cotransporter RNA species appeared in fresh and cultured proximal tubule cells after confluence, repectively. The cultured cells showed reduced Na/glucose cotransporter activity compared to fresh proximal tubules. Primary cultured proximal tubule cells incubated in medium containing 20 mM glucose have reduced ${\alpha}-MG$ transport compared to cells grown in 5 mM glucose. In the proximal tubule cultures incubated in medium containing 5 mM or 20 mM glucose, phlorizin at 0.5 mM inhibited 0.5 mM ${\alpha}-MG$ uptake by 84.35% or 91.85%, respectively. The uptake of 0.5 mM ${\alpha}-MG$ was similarly inhibited by 0.1 mM ouabain (41.97% or 48.03% inhibition was observed, respectively). In addition, ${\alpha}-MG$ uptake was inhibited to a greater extent when $Na^{+}$ was omitted from the uptake buffer (81.86% or 86.73% inhibition was observed, respectively). In cell homogenates derived from the primary cells grown in 5 mM glucose medium, the specific activity of the Na/K-ATPase $(6.17{\pm}1.27\;{\mu}mole\;Pi/mg\;protein/hr)$ was 1.56 fold lower than the values in cell homogenates treated with 360 mg/dl D-glucose, 20 mM $(9.67{\pm}1.22\;{\mu}mole\;Pi/mg\;protein/hr)$. Total $Rb^{+}$ uptake occurred at a significantly higher rate (1.60 fold increase) in primary cultured rabbit kidney proximal tubule cell monolayers incubated in 20 mM glucose medium $(10.48{\pm}2.45\;nM/mg\;protein/min)$ as compared with parallel cultures in 5 mM glucose medium. $Rb^{+}$ uptake rate in 5 mM glucose medium was reduced by 28% when the cultures were incubated with 1 mM ouabain. The increase of the $Rb^{+}$ uptake by rabbit kidney proximal tubule cells in 20 mM glucose could be attributed primarily to an increase in the rate of ouabain-sensitive $Rb^{+}$ uptake $(5\;mM\;to\;20\;mM;\;4.68{\pm}0.85\;to\;8.38{\pm}1.37\;nM/mg\;protein/min)$. In conclusion, the activity of the renal proximal tubular Na,K-ATPase is elevated in high glucose concentration. In contrast, the activity of the Nafglucose cotransport system is inhibited.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.531-535
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• 2011

It was regarded that the $^{31}P$ resonances of inherent nucleotides in $F_1$-ATPase (EF1), as large as 380KDa, could not be observed by $^{31}P$ NMR spectroscopy. However, our $^{31}P$ NMR spectroscopy could differentiate between different nucleotide binding sites on EF1 from Escherichia coli. When EF1 was prepared in the absence of $Mg^{2+}$, EF1 contained only ADP. Multiple $^{31}P$ resonances from $\beta$-phosphates of ADP bound to the EF1 were observed from the enzyme prepared without $Mg^{2+}$, suggesting asymmetry or flexibility amongst nucleotide binding sites. $^{31}P$ resonances from enzyme bound ATP could be observed only from EF1, when the enzyme was prepared in the presence of $Mg^{2+}$. This $Mg^{2+}$ dependent ATP binding was very tight that, once bound, nucleotide could not be removed even after removal of $Mg^{2+}$. $^{31}P$ NMR proved to be a valuable tool for investigating phosphorous related enzymes.

• Biomolecules & Therapeutics
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• v.10 no.1
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• pp.19-24
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• 2002

The effects of a newly synthesized $H^+/K^+$ ATPase inhibitor,1-(2-methyl-4-methoxypheny)-4-[(3-hy-droxypropyl)amino] -6-methyl-2,3-dihydropyrrolo (3,2-c) quinoline (DBM-819) , on the central nervous system, isolated smooth muscle, cardiovascular and digestive systems and renal function were investigated in various experimental animals. Oral administration of DBM-819 had no effect on the central nervous system except body temperature of mice slightly decreased at doses of 15 and 50 mg／kg. DBM-819 produced a moderate analgesic effect in acetic acid-induced writhing test in mice at 50 mg／kg (p.o.). In conscious rats, DBM-819 (15 and 50 mg／kg, p.o.) showed a slight increase in blood pressure and a small decrease in heart rate. DBM-819 had an significant effect on agonist-induced contraction of guinea pig ileum at $1.5{\times}10^{-5}g/ml.$ No significant effect of DBM-819 (5 and 15 mg／kg, i.p) on urinary volume or urinary excretion of $Na^+,\;K^+$ and Cl- was observed in rats. DBM-819 had no significant effect on intestinal transport of a semisolid meal in mice at 15 and 50 mg／kg (p.o.). These findings suggest that DBM-819 exerts no significant pharmacological effects on the central nervous system and renal function at 15 mg／kg (p.o.), but produces some effects on the smooth muscle and circulatory system.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.574-580
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• 2019

ATP drives the conformational change of the group II chaperonin from the open lid substrate-binding conformation to the closed lid conformation to encapsulate an unfolded protein in the central cavity. It is thought that the folding activity of group II chaperonin is strongly correlated with the ATP-dependent conformational change ability. In order to confirm the dependence of the reaction temperature and ATP concentration of PhCpn, the ATPase activities were measured under different reaction temperatures and ATP concentrations. The maximal ATPase activity of PhCpn was observed at 80℃ and 3 mM ATP concentration. As a result of ATPase activity according to the type of salt ions, the highest activity was observed at 300 mM LiCl among the univalent cations and 5 mM MgCl₂ among the divalent cations, respectively. The values of Km and Vmax for ATP substrate were estimated as 2.17 mM and 833.3 μM/min, respectively. This results provide the enzymatic information of PhCpn when the prolonged and high activities of pharmaceutical and industrial proteins (or enzymes), by using chaperonin molecules, are required.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.202-208
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• 1997

In order to investigate the mechanisms of epithelial ion transports, microsomes of soybean roots were prepared and the activity of microsomal ATPases was measured by an enzyme-coupled assay. The effects of various ions were evaluated on the total activity of microsomal ATPases and the average activity was 190 nmol/min/mg protein in the control solution containing $10\;mM\;Na^+\;and\;120\;mM\;K^+$. The activities were increased to 150% and decreased to 63% of the control activity in the solution containing $130\;mM\;K^+$ without $Na^+$ and in the solution containing $130\;mM{\;}Na^+$ without $K^+$, respectively. In general, the activity of microsomal ATPase was increased by$K^+$ in a concentration-dependent manner The activity was also increased at lower pH and relatively higher activities were observed in the pH range of $6{\sim}7$. However, the activity was decreased at weak alkaline $pH\;and{\sim}80%$ of the activity was inhibited at pH 9. Since intracellular $Ca^{2+}$ has been known to control the activity of various enzymes, we have investigated the effects of intra-and extrarnicrosomal $Ca^{2+}$ on the activity of microsomal ATPases. The maximal activity was obtained at the extrarnicrosomal $Ca^{2+}$ concentrations below 1 nM. The activity was gradually decreased by increasing $‘Ca^{2+}’$ concentration and 50% inhibition was observed at ${\sim}500{\;}{\mu}M{\;}Ca^{2+}$. The increase in luminal $Ca^{2+}$ concentration also inhibited the activity of microsomal ATPase. When the influx of external $Ca^{2+}$ was induced by $Ca^{2+}$ ionophore A23187 treatment, the activity was decreased by 30%; however, it was recovered by EGTA-induced chelation of $Ca^{2+}$. These results suggest that the presence of $Ca^{2+}$ regulation sites on both cytoplasmi and luminal sides of microsomal ATPases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.10
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• pp.1500-1509
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• 2014

The object of this study was to investigate the inhibitory effects of chios mastic gum (MG) on gastric acid secretion in an ethanol-induced SD rat model and primary parietal cells. Rats were randomly divided into four groups: Vehicle (normal group), Control (treated with ethanol), MG50 (treated with ethanol and mastic gum at 50 mg/kg b.w), MG100 (treated with ethanol and mastic gum at 100 mg/kg b.w). Groups treated with both MG50 and MG100 showed attenuation of gastric mucosal injury, sub-epithelial loss, hemorrhaging, and gastric juice secretion. We also examined the acidity of gastric juice during gastric injury. Oral administration of both MG50 and MG100 significantly decreased acidity of gastric juice by % and %, respectively. To examine the stimulatory factors related to gastric acid secretion, mRNA expression levels of H2r, M3r, CCK2r, and $H^+/K^+$ ATPase were measured by real-time PCR. Compared with a vehicle group, mRNA expression levels of H2r, CCK2r, and $H^+/K^+$ ATPase clearly increased in the control group. However, levels of H2r, CCK2r, and $H^+/K^+$ ATPase slightly but significantly decreased in MG-treated groups compared with control. Blood level of histamine significantly decreased in MG-treated groups, which indicates the involvement of MG on in histamine-related acid secretion. To identify the mode of action of MG in regulating histamine-related pathways, intracellular level of cAMP and mRNA levels of H2r, M3r, CCK2r, and $H^+/K^+$ ATPase were measured in primary parietal cells. While mRNA levels of M3r and CCK2r remained unchanged, levels of H2r and $H^+/K^+$ ATPase significantly decreased upon MG treatment. Subsequently, intracellular levels of cAMP decreased. These results suggest that mastic gum has the ability to inhibit gastric acid secretion by regulating a histamine-related pathway.

• The Korean Journal of Physiology
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• v.8 no.1
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• pp.55-65
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• 1974

The effect of ginseng on the ATPase activity of rabbit ref cell membrane has been investigated. The experiments were also designed to determine whether the components of ginseng could be attributed to the effect on ATPase activity which dependent upon sodium plus potassium and is sensitive to ouabain. The following results were observed. 1. The activity of the $Na^{+}-K^{+}-ATPase$ from red cell membrane is stimulated by ginseng, and the concentration of ginseng for half-maximal activity is about 15 mg%. The pH optimum for the ginseng sensitive component is 7.6. 2. The portion of the enzyme activity stimulated by ginseng is completely abolished by ouabain. 3. The activating effect of ginseng on the ATPase, with a given concentration of sodium in the medium, is increased by raising the potassium concentration but activity ratio is decreased. 4. The activating effect of ginseng on the ATPase, with a given concentration of potassium in the medium, is increased by raising the sodium concentration but the activity ratio is decreased. 5. The ATPase activity is increased by small amounts of calcium but inhibited by larger amounts and the rate of activity by ginseng is constant. 6. The action of ginseng on the ATPase activity was not related to the sulfhydryl group of cysteine, the amino group of lysine, the imidazole group of histidine, the quanidinium group of arginine, the carboxyl group of aspartic acid, or the hydroxyl group of threonine. 7. The activating effect of ginseng on the ATPase activity may be not due to a saponin which is contained in ginseng.

• The Korean Journal of Food And Nutrition
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• v.10 no.4
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• pp.468-474
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• 1997

This study was designed to investigate the changes in meat quality of beef shank, rib and loin during storage at 8$^{\circ}C$. The shear force value(SFV) of beef shank and loin decreased significantly after 6days storage, beef loin was no significant difference during storage. The SFV in early storage period was high in the order of beef rib, loin and shank, but the SFV of beef rib and loin was similar in course of storage period. The Myofibrillar fragmentation index(MFI) of beef shank increased significantly after 6 days storage, but beef rib and loin early storage was high in the order of beef rib, loin and shank. The actomyosin extractability after 3days storage increased in all parts of beef, but beef loin decreased after 6 days storage. In case of Mg2+-ATPase activity of actomyosin, beef shank increased to 3 days storage, and this reached the level of 0 day after 6days. The MG2+-ATPase activity of beef rib and loin was similar, but beef rib in early storage was higher than beef loin. The Ca2+-TPase activity of beef shank increased to 3 days and decreased after 6 days storage, beef rib was not different during storage and beef loin decreased slightly during storage.

• Applied Microscopy
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• v.18 no.2
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• pp.187-204
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• 1988

The present experiment was performed to investigate the acute and subacute effect of lead acetate on ultrastructural and biochemical changes in mouse diencephalon. In acute case, mouse were peritoneally injected with lead acetate at a dose of 0.26 mmole/kg body weight, and after treatment, mouse were sacrificed at time intervals of 12, 24, 48, and 96 hours. In subacute case, mouse were injected at doses of 0.07 mmoie/kg B. W. and 0.13 mmole/kg B.W. once at two days, and after treatment, mouse wee sacrificed at 1 week, 2 weeks, and 3 weeks. It was observed that after acute treatment, changes composed of increased monoamine oxidase activity, $Na^{+}-K^{+}$ ATPase activity, decreased $Mg^{2+}$-APTase activity, wrinkled myelin, swollen Golgi apparatus and more dense synaptic vesicle in nerve terminal. After subacute treatment, decreased monoamine oxidase activity, increased $Mg^{2+}$-ATPase, $Na^{+}-K^{+}$ ATPase, lose of myelin, uneven mitochondrial distribution, synaptic vesicular density and edema, but at a higher dose the effect was more severe. Therefore, lead acetate caused abnormal change of diencephalon, and at a subacute, it appears metal accumulative toxicity.